Creating a new beamline

A beamline is a collection of devices that can be used together to run experiments, they may be read-only or capable of being set. They include motors in the experiment hutch, optical components in the optics hutch, the synchrotron “machine” and more.

The following example creates a fictitious beamline w41, with a simulated twin s41. w41 needs to monitor the status of the Synchrotron and has an AdAravisDetector. s41 has a simulated clone of the AdAravisDetector, but not of the Synchrotron machine.

from dodal.beamlines.beamline_utils import device_instantiation
from dodal.beamlines.beamline_utils import set_beamline as set_utils_beamline
from dodal.devices.areadetector.adaravis import AdAravisDetector
from dodal.devices.synchrotron import Synchrotron
from dodal.log import set_beamline as set_log_beamline
from dodal.utils import get_beamline_name, skip_device

BL = get_beamline_name("s41")  # Default used when not on a live beamline
set_log_beamline(BL)  # Configure logging and util functions
set_utils_beamline(BL)


"""
Define device factory functions below this point.
A device factory function is any function that has a return type which conforms
to one or more Bluesky Protocols.
"""


"""
A valid factory function which is:
- instantiated only on the live beamline
- a maximum of once
- can optionally be faked with ophyd simulated axes
- can optionally be connected concurrently by not waiting for connect to complete
- if constructor took a prefix, could optionally exclude the BLIXX prefix
""""
@skip_device(lambda: BL == "s41")  # Conditionally do not instantiate this device
def synchrotron(
    wait_for_connection: bool = True, fake_with_ophyd_sim: bool = False
) -> Synchrotron:
    """Calls the Synchrotron class's constructor with name="synchrotron", prefix=""
    If this is called when already instantiated, it will return the existing object.
    """
    return device_instantiation(
        Synchrotron,
        "synchrotron",
        "",
        wait_for_connection,
        fake_with_ophyd_sim,
        bl_prefix=False,
    )

def d11(name: str = "D11") -> AdAravisDetector:
    """
    Also a valid Device factory function, but as multiple calls would instantiate
    multiple copies of a device, discouraged.
    """
    return AdAravisDetector(name=name, prefix=f"{BL}-DI-DCAM-01:")

w41 should also be added to the list of ALL_BEAMLINES in tests/beamlines/test_device_instantiation. This test checks that the function returns a type that conforms to Bluesky protocols, that it always returns the same instance of the device and that the arguments passed into the Device class constructor are valid.